Section 272. Additional requirements for all buildings

No factory shall be
  conducted in any building unless such building shall be so  constructed,
  equipped and maintained in all respects as to afford adequate protection
  against  fire to all persons employed therein, nor unless in addition to
  the provisions of sections two hundred and seventy and two  hundred  and
  seventy-one such buildings shall conform to the following requirements:
    1.  Access to exits. Every exit shall be maintained in an unobstructed
  condition. Safe and continuous passageways with an unobstructed width of
  at least three feet throughout their  length  and  leading  directly  to
  every  exit  including  fire  escapes  and  passenger elevators shall be
  maintained at all times on every floor of the building.
    2. Stairways. Stairways shall be  provided  with  proper  hand  rails.
  Where the stairway is enclosed by fireproof partitions the bottom of the
  enclosure  shall  be  of  fireproof material at least four inches thick,
  unless such partitions extend to the cellar bottom. If safe  egress  may
  be  had  from the roof to an adjacent structure all stairways serving as
  required exits and extending to the top story shall be continued to  the
  roof.
    3.  Doors  and  windows. No door leading into or out of any factory or
  any floor thereof shall be locked, bolted  or  fastened  during  working
  hours.  No  door on any floor shall be obstructed by metal bars, grating
  or wire mesh. Metal bars, grating or wire mesh provided for  any  window
  or  other  opening  shall  be so constructed as to be readily movable or
  removable from the inside so as to  afford  free  and  unobstructed  use
  thereof  as  a  means  of  egress and they shall be left unlocked during
  working hours. Every door opening on a stairway or other exit shall open
  from both sides so as not to obstruct passage. Doors opening directly to
  the street or to yard or open area, may be provided with panic bolts  of
  an approved type.
    4.  Exit signs. An exit sign shall be placed over all openings leading
  to stairways and other exits. Such sign shall be legible and visible  in
  accordance  with  rules,  regulations or requirements established by the
  State of New York Board of Standards and Appeals.
    5. Vertical openings. All vertical openings leading from one floor  to
  another,  except  one created by a mezzanine floor, shall be enclosed by
  fire-proof or  fire-resistive  materials  and  ventilated  in  a  manner
  conforming to rules adopted by the board.
    6.  Floors.  Floors  in  buildings  more  than  one and less than five
  stories in height erected after October first, nineteen hundred thirteen
  and in all buildings erected prior thereto shall be  so  constructed  or
  provided with a protective ceiling as to have a fire-resistive rating of
  at  least  one  hour.  This  subdivision  shall  not apply where factory
  buildings are provided throughout with an automatic  fire  extinguishing
  system approved in the city of New York by the fire commissioner in such
  city and elsewhere by the commissioner.
    7.  Regulations  by  board.  The  board  may adopt rules and establish
  requirements and standards for construction, equipment  and  maintenance
  of  factory buildings or of particular classes thereof and the means and
  adequacy of exit therefrom in order to carry out the  purposes  of  this
  chapter, alternative or in addition to the requirements of this article,
  and not inconsistent with the spirit thereof.